Cryptology ePrint Archive: Report 2020/191

Lattice-Inspired Broadcast Encryption and Succinct Ciphertext-Policy ABE

Zvika Brakerski and Vinod Vaikuntanathan

Abstract: We propose a candidate Ciphertext-Policy Attribute Based Encryption (CP-ABE) scheme for circuits, with ciphertext size that depends only on the depth of the policy circuit (and not its size). This, in particular, gives us a Broadcast Encryption (BE) scheme where all parameters (in particular, the size of the keys and ciphertexts) have a poly-logarithmic dependence on the number of users, a task that was only known to be achievable assuming ideal multilinear maps or indistinguishability obfuscation. Our construction relies on techniques from lattice-based (and in particular LWE-based) cryptography, but we are unable to provide a security proof. We analyze some attempts at cryptanalysis.

Category / Keywords: foundations / Broadcast encryption, ciphertext-policy ABE, lattices, learning with errors

Date: received 15 Feb 2020

Contact author: vinodv at mit edu

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Version: 20200218:090813 (All versions of this report)

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